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 *
 * Software License Agreement (BSD License)
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 * Author: Eitan Marder-Eppstein
 *         David V. Lu!!
 *********************************************************************/
#ifndef _EXPANDER_H
#define _EXPANDER_H

#include <global_planner/potential_calculator.h>
#include <global_planner/planner_core.h>

namespace global_planner
{

class Expander
{
public:
    Expander(PotentialCalculator *p_calc, int nx, int ny) :
            unknown_(true), lethal_cost_(253), neutral_cost_(50), factor_(3.0), p_calc_(p_calc) { setSize(nx, ny); }

    virtual ~Expander() {}

    /** 计算路径代价的函数
     * @param costs      代价地图的指针
     * @param start_x    起点坐标
     * @param start_y
     * @param end_x      终点坐标
     * @param end_y
     * @param cycles     循环次数
     * @param potential  代价数组
     * @return
     */
    virtual bool calculatePotentials(unsigned char *costs, double start_x, double start_y,
            double end_x, double end_y, int cycles, float *potential) = 0;

    /** 设置或重置地图的大小
     * @brief  Sets or resets the size of the map
     * @param nx The x size of the map
     * @param ny The y size of the map
     */
    virtual void setSize(int nx, int ny)
    {
        nx_ = nx;
        ny_ = ny;
        ns_ = nx * ny;
    }

    void setLethalCost(unsigned char lethal_cost) { lethal_cost_ = lethal_cost; }

    void setNeutralCost(unsigned char neutral_cost) { neutral_cost_ = neutral_cost; }

    void setFactor(float factor) { factor_ = factor; }

    void setHasUnknown(bool unknown) { unknown_ = unknown; }

    void clearEndpoint(unsigned char *costs, float *potential, int gx, int gy, int s)
    {
        int startCell = toIndex(gx, gy);
        for (int i = -s; i <= s; i++)
        {
            for (int j = -s; j <= s; j++)
            {
                int n = startCell + i + nx_ * j;
                if (potential[n] < POT_HIGH) continue;
                float c = costs[n] + neutral_cost_;
                float pot = p_calc_->calculatePotential(potential, c, n);
                potential[n] = pot;
            }
        }
    }

protected:
    inline int toIndex(int x, int y) { return x + nx_ * y; }
    int nx_, ny_, ns_; /**< size of grid, in pixels */
    bool unknown_; // 是否允许探索未知
    unsigned char lethal_cost_, neutral_cost_;
    int cells_visited_;
    float factor_; // 代价值
    PotentialCalculator *p_calc_;

};

} //end namespace global_planner
#endif
